Pressurized medium motor

ABSTRACT

A pressurized medium motor comprising a housing, a plurality of opposed pivotally mounted piston and cylinder units in the housing and adapted to be successively supplied with pressurized medium, each unit acting on eccentric drive means geared positively or non-positively with the housing, the opposed piston and cylinder units with the eccentric drives forming a polygon having a substantially constant circumference with varying side lengths, with an adjacent pair of units each having one piston end acting on a common eccentric part of an eccentric drive, each such unit being provided with at least one passage acting as a supply or discharge means for the pressurized medium, the said passage(s) being alternately connected automatically to pressure and exhaust passage, the said pressure and exhaust passages being connected in turn to all the units.

nited States Patent linkhammer [151 3,656,405 [451 Apr. 18, 1972 [54]PRESSURIZED MEDIUM MOTOR [21] Appl. No.: 88,446

FOREIGN PATENTS OR APPLICATIONS 1,924,837 l/l970 Germany ..92/75 PrimaryExaminer-Paul E. Maslousky Attorney-Edmund M. Jaskiewicz [57] ABSTRACT Apressurized medium motor comprising a housing, a plurality of opposedpivotally mounted piston and cylinder units in the housing and adaptedto be successively-supplied with pres surized medium, each unit actingon eccentric drive means geared positively or non-positively with thehousing, the opposed piston and cylinder units with the eccentricdrives'forming a polygon having a substantially constant circumferencewith varying side lengths, with an adjacent pair of units each havingone piston end acting on a common eccentric part of an eccentric drive,each such unit being provided with at least one passage acting as asupply or discharge means for the pressurized medium, the saidpassage(s) being alternately connected automatically to pressure andexhaust passage, the said pressure and exhaust passages being connectedin turn to all the units.

8 Claims, 4 Drawing Figures 100 27a 2s 3o 16 27h PATENTEUAPR 18 ma SHEET2 0F 2 l fw fr@ I L LLL lNvliN'l'olz:

Karl Klinkhummer PRESSURIZED MEDIUM MOTOR Prior Application In Austriaon Nov. l1, l969 and numbered A 10578/69 The invention concerns a motoradapted to be driven by means of a pressurized medium such as a liquidor air.

lt is an object of the invention to provide a pressurized medium motorwhich is relatively small but yet provides a high torque without the useof reduction gears and which can operate continuously.

ln accordance with the invention there is provided a pressurized mediummotor in a housing, having a plurality of opposed piston and cylinderunits adapted to be supplied with pressurized medium, the units beingpivotally mounted and connected with the eccentric drive means runningon the inside surface ofthe housing, each opposed piston and cylinderunit being provided with at least one pressurized medium passage to actas inlet and outlet, the said passage being connected alternately andautomatically to pressurized medium passages for the inlet and outlet ofthe pressurized medium associated with each opposed piston and cylinderunit.

Preferably each opposed piston and cylinder unit is provided with twopressurized medium passages which are alternately connected with apressurized medium supply and medium discharge common to all such units.The opposed piston and cylinder units with their eccentric drives form apolygon of varying shape, the lengths of the sides varying in dependenceupon the positions of the various pistons while the circumference of thearticulated polygon remains substantially constant.

Adjacent opposed piston and cylinder units each have a piston endsupported on an eccentric part of a common drive, the pistons exertingpressure on the eccentric to produce the drive.

The drive means form with the housing a reduction gear; to this end theeccentrics may be provided with gear pinions which mesh with a toothedinside surface ofthe housing; alternatively the eccentrics are providedwith friction gears which engage with a smooth inside surface of thehousing to produce a friction drive.

The opposed piston and cylinder units and the eccentric drives aremounted pivotally or rotatably in common bearing plates. Each opposedpiston and cylinder unit has a cylinder block in the bore of which twoopposed pistons are displaceably mounted, and held against the adjacenteccentrics by means ofa spring.

Two passages extending from the cylinder bore of each cylinder blocktowards the housing center, act as supply and discharge passages and areconnected alternately to two supply and discharge passages locatedwithin a bearing plate on different levels, and to an annular chamberconnected to the supply or discharge passages which supplies thepressurized medium and provides a discharge path.

The pistons ofthe units are supplied in succession with the pressurizedmedium and each unit operates on particular eccentrics so that asubstantially uniform drive results on the housing or bearing plate.

During rotation of an eccentric drive means, the associated opposedpiston and cylinder units execute a pendulum motion about the region ofthe supply and discharge passages associated with each unit on thebearing plate, so that the passage from the cylinder block isalternately connected to the supply and discharge passages on thebearing plate side and hence to the central passages.

The motor of the invention is of simple structure, reliable in operationand economical to produce.

An advantage of the invention resides in that the motor is provided witha built-in reduction gear thus rendering additional gears superfluous.This motor is a slow speed runner which has a high torque which isconstant over its whole speed range. This torque is readily varied byvarying of the operating medium.

Owing to the arrangement of the opposed piston and cylinder units whichengage the housing to be rotated at a fairly large radius relative tothe axis of rotation,

balanced torque is obtained; the gear ratio obtained between the pistonand cylinder units and the drum renders extra gearing superfluous.

A motor in accordance with the invention provides a shockproof startunder load from any position, and permits an accurately predeterminedacceleration and deceleration characteristic.

The motor also affords accurate load, speed, and revolution control andcan be used as a positioning device.

The motor is applicable more particularly to lifting tackle, the liftingheight and load being under exact control.

The motor may be incorporated as a direct drive in pulleys such as cabledrums, wheel bosses or the like.

Reference should now be made to the accompanying drawings in which:

FIG. l is a cross section through a motor having a plurality of opposedpiston and cylinder units pivotally mounted in a housing;

FIG. 2 is a section through an opposed piston and cylinder unit taken onthe line I-I in FIG. 1,

FIG. 3 is a section through the same motor taken on the line II-II ofFIG. l,

FIG. 4 is a developed view of the connecting passages in the region ofthe ringed portion A in FIG. 3.

A pressurized medium motor, more particularly a hydraulic motor has ahousing 10 in which a plurality of opposed piston and cylinder units 11,l2, 13, 14 and mounted pivotally and successively supplied with apressurized medium such as oil or air.

The opposed piston and cylinder units 1l to 14 are connected witheccentric drives 15, 16, 17, 18 which are positively or frictionallycoupled to the housing, so that the eccentric drives l5 to 18 produce arotational connection between the units 11 to 14 and the housing l0.

The housing 10 is circular, but may also be made as an oval. In thehousing 10 there are four opposed piston and cylinder units 11 to 14together with four eccentric drives 15 to 18, so that each two adjacentunits 1l to 14 cooperate with one eccentric drive 15 to 18.

lt is possible to provide the housing 10 with three or with `more thanfour, for example, six or eight units and corresponding eccentricdrives.

Each opposed unit l1 to 14 is provided with at least one pressurizedmedium passage as supply or discharge, which is alternately andautomatically connectable with fluid medium passages to effect forwardmotion or reverse motion of the units l1 to 14.

As shown, each opposing unit 14 is provided with two pressurized mediumpassages 19, 20 as supply or discharge passages, which are alternatelyconnected automatically with a central medium forward motion passage 21and a central medium reverse motion passage 22, the passages beingcommon to all units.

The opposed piston and cylinder units 11 to 14 with their eccentricdrives l5 to 18 form a movable polygon having sides of varying lengthwhile the circumference of the polygon remains substantially constant.

All units 1l to 14 are of identical formation. Thus, each unit 1l to 14is provided with a cylinder block 23 which is pivotally mounted onlateral bearing plates 25a and 25b having two central bearings 24aligned at right angles to the direction of piston movement. Each unit11 to 14 has a cylinder bore 26 in its cylinder block 23 in which twoopposed pistons 27 are displaceably mounted.

The end 27a of each piston 27 has an abutment surface 27b which is ofless cross-sectional area than the associated piston, and the end may bestepped.

The eccentric drives 15 to 18 with the housing 10 form a reduction gear.For effecting a positive connection between the eccentric drives 15 to18 and housing 10, the housing l0 is provided on the inside surface withan internal toothed ring 10a with which the eccentric drives 15 to 18mesh by means of a high pinions 32 provided on both sides of theeccentric 30.

A non-positive connection between the eccentric drives 15 to 18 andhousing l0 to form a reduction gear may be frictional, thus the insidesurface of the housing is provided with a smooth surface and the pinionsof the crank drives 15 to 18 are replaced by friction wheels or rollers.

As shown, the piston and cylinder units l1 to 14 and their mountingplates are stationary and the housing is rotatable. Alternatively thehousing 10 may be stationary and the units 11 to 14 with their mountingplates may be rotatable within the housing 10.

Each unit 11 to 14 is provided in its cylinder block 23 with twopressurized medium passages 19, 20 acting as supply or dischargepassages, these passages being preferably at right angles to thedirection of piston movement and arranged radially and parallel, side byside, in the bearing extensions, in the region of a bearing plate 25a or2517. These two pressurized medium passages 19, 20 are connected to thechamber 26 via a common axial connecting passage 33. Within the bearingplate 25a or 25b, and near the two pressurized medium passages 19, 20each cylinder block 23 has two pressurized medium passages 34, 35associated therewith as supply or return passages at different levelsrelative to one another, which passages are connected to the forward andreverse fluid passages 21, 22. The two annular chambers 36, 37 areseparated by a distance corresponding to the distance between thepassages 19, 20, and are formed by axial annular grooves which on thecasing side are located in a shaft 38 and connected by the upstream anddownstream flow of the medium. The passages 34, 35 alternately connectthe pressurized medium passages 19, 20 of the cylinder blocks 23 tocorresponding annular grooves 36, 37; the passages 34, 35 are spaced tocorrespond with the spacing of the passages 19, 20 and annular grooves36, 37.

The pivotal point of each unit 1l to 14 is at a greater radius than thelength of the orifices of the supply and discharge passages 34, 35together with the cylinder block-side passages 19, 20. The inlet andoutlet passages 21, 22 lead into the annular grooves 36, 37 via passages21a, 22a extending outwards at an angle.

Two opposite units 11 and 13, or 12 and 14, are actuated in oppositionto each other, so that if one unit is coupled to the pressure supply theother unit is coupled to the exhaust. In the position of the units 1l to14 as shown in FIG. 1 of' the drawings unit 11 is located in the chargeposition, i.e. the pistons 27 of unit 11 are being supplied withpressurized medium; they are pushing oppositely outwards and thus act onthe two eccentric drives and 16. Unit 12 is at the beginning of a powerstroke i.e. the pistons 27 of this unit are located in the retractedposition one against the other, and are about to be supplied withpressurized medium; unit 13 is connected to exhaust and unit 14 is aboutto be so connected.

The mode of operation ofthe motor is as follows:

As shown, unit ll is located in a driving position, with its pressurizedfluid passage 19 connected to the annular supply groove 36 via theinclined supply passage 34, in which groove the supply passage 21 of themedium ends. The pressurized medium flows from the passage 2l via theannular groove 36, the inclined passage 34, the supply passage 19 andthe connecting passage 33 into the cylinder space 26, acts on the twoopposed pistons 27 and presses them outwards. These two pistons now acton the eccentric 30 of the two drives 15 and 16 which are positivelyconnected to the housing, and impart rotation thereto (see direction ofarrow on the eccentric, in FIG. 1). The eccentric drives 15, 16 alsoengage the housing l0 and rotate it in the same direction (see externalarrow, FIG. 1).

The action of the unit 11 rotates all the eccentric drives 15 to 18 andduring this rotation all units 11 to 14 pivot about their bearingextensions 24. The opposed pistons 27 of unit 11 continue to press onthe two eccentric parts 30 of the drives 15, 16 until the unit assumesdead center position, i.e. until the eccentrics are fully extended inline with the longitudinal axes ofthe pistons. In this position fillingthe unit 11 and its action to rotate the eccentric drives are ended. Therotation of the drives causes all units 11 to 14 to be pivotally moved,so that unit 12 now assumes a filling position and unit 14 an emptyingposition, while the two opposite units 11 and 13 are at a zero position.During filling of unit 11, unit 13 was in the emptying position and thetwo units 12, 14 passed through a zero posi tion their passages 19, 20are blocked between the two inclined supply and discharge passages 34,35. Filling of unit 12 commences before unit 11 is completely filled, sothat the piston driving actions merge into and overlap one another, oneunit taking up the drive before the end of the drive of the previousunit to provide continuous rotation of the housing. Unit 12 nowprogressively rotates the two eccentric parts 30 of the drives 16 and17, all units 11 to 14 being pivoted, and unit 14 is emptied. The twoother units 11, 13 have their supply and discharge passages 19, 20 swungbetween the two inclined passages 34, 35 towards the upstream (ordownstream) passage; thus unit 1l moves so as to become connected to thereturn exhaust passage 35, and unit 13 so as to become connected to thesupply passage 34. When the filling of unit 12 is completed, unit 13 hasits supply passage 19 connected to the supply passage 34 and is filledin turn. At the same time unit 11 has its discharge passage 20 coupledto exhaust passage 35 and can thus be emptied. After unit 13 is filled,the oscillation of the units moves unit 14 into the filling positionwhile unit 12 is emptied.

The two supply and discharge passages 19, 20 of all units 1l to 14 thusmove, due to the pivotal mounting of the cylinder blocks, between theinclined supply and exhaust passages 34, 35 associated with each unit 11to 14 and hence the cylinders arrive successively in a filling position.

The annular groove 36 connected to the supply of the medium, and thesupply passage 34 leading thereto, are constantly under pressure. Themovement of the supply and discharge passages 19, 20 on the cylinderblock side is shown in FlG. 4 by the arrow. A slight overlap of thesupply passage 19 with the inclined supply passage initiates filling,and complete register of both passages 19, 34 provides maximum supply tothe pistons 27 with pressurized medium. Near the end stage of filling,the supply passage 19 swings over the supply passage 34 and thus becomesonly partly in register therewith.

The displacement of the opposed pistons 27 of each unit 11 to 14 causesrotation of the eccentric drives l5 to 18 and hence rotation of thehousing 10. Each drive 15 to 18 is rotated through a predeterminedangular region of rotation and then a subsequent unit takes over furtherrotation, so that the various drives are translated into a uniformrotary movement ofthe housing.

Compression springs 31 retain each unit 11 to 14 in connection with thedrives l5 to 18, so that during rotation of the drives a correspondingpivotal movement of the units 11 to 14 occurs so that their two supplyand discharge passages 19, 20 are caused sequentially to assume afilling position (connection of passage 19 with passage 34), a zeroposition (passage 19 assumes a position between the two passages 34,35), or an emptying position (discharge passage 20 connected todischarge passage 35).

It is within the scope of the invention to provide each unit 11 to 14only with one passage to act as both inlet and outlet, and this passagemay be bifurcated in the region of the supply and discharge passages 34,35.

Iclaim:

1. A pressurized medium motor comprising a housing, at least one baseplate, a plurality of opposed piston and cylinder units within saidhousing and mounted on said base plate; bearing extensions on said unitswhereby each said unit can rock about a center; eccentric drives actedupon by said pistons, driving means interconnecting said drives and saidhousing, said piston and cylinder units together with said eccentricdrives forming a polygon having a constant circumference but with sidesof variable length depending on the positions of said pistons; onepiston of each pair of adjacent piston and cylinder units acting on asingle one of said eccentric drives; at least one pressurized mediumpassage to each unit; and fluid supply and exhaust passages alternatelyconnectable to each piston and cylinder unit as a result of rotation ofsaid motor.

2. A pressurized medium motor as recited in claim l, further comprisingtwo fluid passages for each said opposed piston and cylinder unit, acommon pressurized medium supply and a common exhaust for all saidunits, and means for connecting said units in a predetermined sequenceto said supply and exhaust via said two passages.

3. A pressurized medium motor as recited in claim 1 wherein all opposedpiston and cylinder units are of identical construction, characterisedby location of said units in diametrically opposite pairs, with meansfor actuating the units of a pair in opposite sense.

4. A pressurized medium motor as recited in claim l comprising a toothedring located inside said housing, and at least one pinion wheel on eachsaid eccentric drives meshing with said toothed ring to form a reductiongear.

5. A pressurized medium motor as recited in claim l comprising twoparallel base plates, bearing pins on said eccentric drives and bearingextensions on said units, and bearing surfaces defined by said plates toreceive said bearing pins and bearing extensions so that said eccentricdrives can rotate and said units can rock.

6. A pressurized medium motor as recited in claim 5 characterized by thefeature that each eccentric drive comprises an eccentric of cylindricalform, said eccentric being secured to said bearing pins and to at leastone pinion wheel.

7. A pressurized medium motor as recited in claim l, wherein eachopposed piston and cylinder unit consists of a cylinder block dening abore therein; two oppositely moving pistons located in said bore; acompression spring between said pistons, a rod extension of each saidpiston of reduced section and extending outwards of said cylinder, andan eccentric-engaging surface on the outward end of each said rodextension.

8. A pressurized medium motor as recited in claim 7, wherein a bearingextension of each cylinder block defines two passages one to supplypressure medium and one for exhaust, said passages being arranged at anangle to the direction of piston movement and parallel to one another,said two passages joining one end of a common connecting passageextending along the axis of said bearing extension, the other end ofsaid common passage terminating in the respective cylinder bore, andwherein one bearing plate denes two annular passages as supply orexhaust for said medium, said annular passages being common to all saidopposed piston and cylinder units and being in fluid transmittingconnection with said passages in said bearing extension.

1. A pressurized medium motor comprising a housing, at least one baseplate, a plurality of opposed piston and cylinder units within saidhousing and mounted on said base plate; bearing extensions on said unitswhereby each said unit can rock about a center; eccentric drives actedupon by said pistons, driving means interconnecting said drives and saidhousing, said piston and cylinder units together with said eccentricdrives forming a polygon having a constant circumference but with sidesof variable length depending on the positions of said pistons; onepiston of each pair of adjacent piston and cylinder units acting on asingle one of said eccentric drives; at least one pressurized mediumpassage to each unit; and fluid supply and exhaust passages alternatelyconnectable to each piston and cylinder unit as a result of rotation ofsaid motor.
 2. A pressurized medium motor as recited in claim 1, furthercomprising two fluid passages for each said opposed piston and cylinderunit, a common pressurized medium supply and a common exhaust for allsaid units, and means for connecting said units in a predeterminedsequence to said supply and exhaust via said two passages.
 3. Apressurized medium motor as recited in claim 1 wherein all opposedpiston and cylinder units are of identical construction, characterisedby location of said units in diametrically opposite pairs, with meansfor actuating the units of a pair in opposite sense.
 4. A pressurizedmedium motor as recited in claim 1 comprising a toothed ring locatedinside said housing, and at least one pinion wheel on each saideccentric drives meshing with said toothed ring to form a reductiongear.
 5. A pressurized medium motor as recited in claim 1 comprising twoparallel base plates, bearing pins on said eccentric drives and bearingextensions on said units, and bearing surfaces defined by said plates toreceive said bearing pins and bearing extensions so that said eccentricdrives can rotate and said units can rock.
 6. A pressurized medium motoras recited in claim 5 characterized by the feature that each eccentricdrive comprises an eccentric of cylindrical form, said eccentric beingsecured to said bearing pins and to at least one pinion wheel.
 7. Apressurized medium motor as recited in claim 1, wherein each opposedpiston and cylinder unit consists of a cylinder block defining a boretherein; two oppositely moving pistons located in said bore; acompression spring between said pistons, a rod extension of each saidpiston of reduced section and extending outwards of said cylinder, andan eccentric-engaging surface on the outward end of each said rodextension.
 8. A pressurized medium motor as recited in claim 7, whereina bearing extension of each cylinder block defines two passages one tosupply pressure medium and one for exhaust, said passages being arrangedat an angle to the direction of piston moveMent and parallel to oneanother, said two passages joining one end of a common connectingpassage extending along the axis of said bearing extension, the otherend of said common passage terminating in the respective cylinder bore,and wherein one bearing plate defines two annular passages as supply orexhaust for said medium, said annular passages being common to all saidopposed piston and cylinder units and being in fluid transmittingconnection with said passages in said bearing extension.